Fuse plug



April` 5,1927. 1,623,819

O. H. VAN AMBURG FUSE PLUG Filed Dec'. 19, 1923 Inventor:

I Hi sAtxborneg- Patented Apr. 5, 1927.

UNITED; STATES' PATENT OFFICE.

TTO H. VAN AMBURG, 0F BRIDGEPORT, CONNEYCTICUT,v ASSIGNOR TOGENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

FUSE PLUG.

Application filed December 'l'he present invention relates to thermal safety devices for electric circuits and more especially to reloadable fuse plugs.

The object of my invention is the provi- ;'s sion of an improved fuse plug in which the 'ljuslbe element may be renewed with facility without the use of tools and which may be manufactured at low cost.

One embodiment of the invention is shown t: in the accompanying drawing in which Fig. 1 a vert-ical section of a complete plug; Fig. 2 is a similar section of the insulating top with the side contact attached thereto; Fig. 3 is asimilar section of the inner 1nsulating tube with the fusible element in position; Fig. t is a similar section of the insulating bottom shell with the center contact attached thereto; and Fig. 5 is a perspective view showing method of assembly il) of certain parts.

The side contact 1 is a metal cylinder with a closed upper end 2 and an open lower end with the usual screw thread 3 formed in the lower portionof the cylinder; while between the threaded portion and the upper end the cylindrical wall 4 is provided with pairs of longitudinal slits 5 and the metal bridges 6 between them forced inwardly to provide yieldable friction means to be referred to below.

The upper end of the side contact cylinder 1 is enclosed by an insulated handle portion in the form of a porcelain cap 7 and the two parts are permanently7 connected by a circular contact plate 8 having integral arms 9 which pass through holes 10 in the upper end 2 of the side contact shell and corresponding holes 11 in the top of the 1nsulating cap 7 and are clenched over the bottomof ay mortise 12 extending` from the outer surface of the cap part way through the top wall thereof. After the arms 9 are clenched over. the mortise 12 is filled with cement 13.

The insulating bottom shell 14 is of porcelain with its upper end open and an end wall 15 provided at its lower end through which the center contact 16' extends. The side wall cylindrical and of a diameter to bear lightly against the inner surfaces of the bridge pieces G when it is introduced into the side contact shell 1. Notches 17 are formed in the periphery of the lower end to provide a good hand hold. The center contact 1G is in the form of a stud with a 19, 1923. Serial No. 681,606.

large head 18 seated againstthe interior surface of the end wall 15 and its shank 19 extending therethrough and headed. over a washer 2() on the outer surface thereof.

The supportforthe fusible element is in the form of an inner insulating tube 21 of tough material such `as horn liber and is cylindrical with both ends open. ameter of the tube 21 is sulliciently small to permit it to be assembled with clearance in the bottom shell 14 and its length is such that when so assembled its upper end projects slightly above the upper end of the bottom shell.

The fusible element 22 is preferably of the form shown and described in the Weston The diy Patent 1,441,550; January 9, 1923, but any of being readily detached without the usev of tools. When the assembled plug is screwed home in the ordinary cutout block or receptacle, the lower shell .14 will be forced inwardly of the side Contact shell 1 and ensures good contact between the ends of the fusible member 22 and the center contact 16 and the Contact plate 8 respectively.

lhen the fusible element 22 becomes blown or disrupted, the gases evolved become cooled as they come in contact with the extended inner and outer surfaces of the inner tube 21, the inner and outer surfaces of the lower' shell 14; and the inner surface of the side contact shell 1, so that upon escaping from the latter they are harmless.

While l have shown and described the best embodiment of the invention known to me. l do not desire to be restricted thereto.

lVhat I claim as new and desire to secure by Letters Patent of the United States, is:

1. A fuse plug comprising an insulated threaded side contact shell7 a lower shell of insulation provided with a center contact and adapted to be telescopically assembled detachably within said side contact shell, a longitudinal bridge on said contact shell adapted to frictionally retain said lower lOl) llO

shell therein, and a fusible elementsupport adapted to be assembled detachably within said lower shell and to support the ends of the fusible element in engagement with Said side Contact shell and seid Center Contact.

2. A fuse plug comprising 'a threded Cylindrical side Contact shell having one end closed, an insulating handle attached to the closed end of said shell, :L lower shell provided with a, center Contact, means to telescopically receive and frctionally retain said lower Shell Within said side Contact shell and a tubular support for the fusible element adapted to be assembled within said lower shell and to support the ends of the fusible element in engagementV with said center Contact :1nd the closed end of said side Contact shell.

3. A fuse plug comprising a tubular side Contact shell having one end closed7 an insulating Cap surrounding said closed end, uy Contact plate engaging the inner surface of said Closed end and having eleneh eXtensione therefrom passing through and yanchoring said. side Contact shell to seid cup, a lower `shell of insulation having one end closed and provided with av headed center vontact, frietioinil ineens for holding Said lower shell Within seid side Contact shell, and a tube of insulation adapted to be asleembled Within said lower shell and to support a fusible member in engagement with said Contact plate :and said headed Center Contact.

In witness whereof, I have hereunto set my hund this 13th day of December 1923.

OTTO H. VAN AMBURG. 

